What is BLACKLIGHT PRINT?
This is inkjet printing using ink that emits full color when exposed to UV light.
By overlapping with normal ink, a single picture changes. The use of this inkjet printing technology is expanding from conventional applications such as single-color hidden marking and security to signs, displays, show windows, and space production in commercial facilities.
Types of triggers to change the design of a BLACKLIGHT PRINT
UV handy light
It is a printing technology that emits full-color light when irradiated with a black light, which is invisible under normal light. since it absorbs UV light and emits its own light, it can reproduce colors that cannot be expressed with reflective colors CMYK, and it can reproduce colors using the three primary colors of light with depth.
About raw materials
The raw material for the ink is a rare earth (powder) that emits light under ultraviolet light. Depending on the raw material, it is possible to make pigments that glow in the three primary colors (RGB) of red, blue, and green, which are excited by near-ultraviolet light (360-400 nm) and emit strongly.
※Excitation light: General term for light that causes excitation in materials such as phosphors.
※Wavelengths vary depending on the pigment.
About color reproduction
CMYK is the basis for printing, but color reproduction in this printing is based on the three primary colors of light using RGB: R (red), G (green), and B (blue), and mixing these three colors results in white.
- A:It looks black because black light ink is not printed on it.
- B:It appears to be white depending on the three primary colors of light.
※All white background areas of the BLACKLIGHT PRINT emit light. If you don't want it to glow, you need to make the background transparent or black.
- C:Where all RGB inks are printed.
- D:Areas that are not printed at all
※By darkening the environment, the area where ink is not applied appears black.
About fluorescent whitening agents
There are two types of paper: one with optical brighteners and one without.
In the photo, the paper on the right does not contain optical brighteners, so the printed area glows beautifully. The paper on the left, on the other hand, contains optical brighteners, so when you shine a black light on it, the paper itself glows blue.
The peak wavelength of the irradiated black light and the wavelength adjustment performed during the printing process can greatly affect the way the image looks.
The above images are set to print at different peak wavelengths (from top left, peak wave 365nm/370nm/375nm/380nm).These photos were taken by irradiating the image with a black light peak wave of 370 nm.
(Left) It can be seen that if the peak wavelength of the irradiation and the wavelength setting of the printing are the same, the color will be accurate, while if the wavelength of the irradiation and the wavelength setting of the printing are different, the color of the printed material will look different.
As for weatherability, it is greatly affected by the media used, the lighting used (wattage and distance), and the environment used (sunlight). In addition, fading is caused by exposure to UV light (ultraviolet rays). Therefore, if the product is not exposed to UV light (ultraviolet rays), the color will not fade. The color will not fade if it is not exposed to UV light, such as in a dark place without sunlight or on a page of a magazine that is usually closed.
|Distance from light source||10cm~under 30cm|
|Basic number of days for color fading||About 15 days|
When the distance between the printing paper and UV light source is less than 30cm, the color will fade extremely fast. Be careful when the distance between the light source and the printing paper is less than 30cm.
|Distance from light source||30cm~under 80cm|
|Basic number of days for color fading||About 90 to 180 days|
If the distance between the printing paper and the UV light source is more than 30cm, the color will fade at a slower rate. The weather resistance is calculated based on this distance.
|Distance from light source||More than 80cm|
|Basic number of days for color fading||About 180 to 365 days|
If the distance between the printing paper and the UV light source is more than 80cm, the weather resistance will be dramatically improved. This is the basic distance for wallpaper.
|Paper used in the verification||Inkjet plain paper|
|Light||[Popular Type 18/G13] 375nm 40" Straight Tube LED Blacklight Fluorescent Lamp
UV radiation intensity 66μW/cm² at 100cm from main body
Emission spectrum 375nm
|Irradiation time per day||8 hours|
|The weather resistance is specified based on "appropriate distance and appropriate wattage".
*Evaluation values for black light printing since October 2010.
How does the color fade?
There is a difference in the fading process depending on the RGB color, with the first color to fade being red, followed by blue, and then green. Since each color fades at a different rate, the number of fading days is determined by the point at which the color balance is lost and the product becomes unusable. Therefore, depending on the color, the number of days may be longer than indicated. Weatherability varies greatly depending on the output of the UV light source, even at the same distance. If you do not use the appropriate wattage, the color may fade extremely quickly.
Relationship between lighting distance and wattage to weather resistance